You said that as joke, but really I want to understand how this could even occur. I am in Japan and such behaviour is inconceivable. Even as an extreme outlier.

What has to happen / not happen in someone's life, where that kind of calculus becomes possible?

My naive guess is that this is a problem of socialisation, which allows - even encourages - ass-holery of many kinds. Wherever "Fuck you, buddy" is thought of as a smart way to get ahead, public toilets will not remain clean.